The invention relates to aqueous formaldehyde-free compositions that include hydroxy functional, carboxy functional polymers.
Fibrous glass insulation products generally include glass fibers bonded together by a cured thermoset polymeric composition. Processes for making fiberglass insulation generally include drawing molten streams of glass into fibers of random lengths that are blown into a forming chamber where they are randomly deposited as a web onto a traveling conveyor. The fibers, while in transit in the forming chamber and while still hot from the drawing operation, are sprayed with an aqueous binder composition, e.g., a formaldehyde-based binder. The residual heat from the glass fibers and the flow of air through the fibrous mat during the forming operation are generally sufficient to volatilize the majority to all of the water from the binder, thereby leaving the remaining components of the binder on the fibers as a viscous or semi-viscous high solids liquid. The coated fibrous web is then transferred to a curing oven where heated air is blown through the web to cure the binder and bond the glass fibers together.
During the curing reaction, formaldehyde and low molecular weight phenol-formaldehyde compounds are volatilized from the composition and into the surrounding environment, which is undesirable for the people working around the fiberglass insulation manufacturing process and may be harmful to the environment.
A number of formaldehyde-free fiberglass binder compositions have been developed. Some of these compositions include α,β-ethylenically unsaturated carboxylic acid polymers, polyols and condensation accelerators. These compositions are applied to glass fibers and then dried in ovens at high temperatures to effect crosslinking. A portion of the lower molecular weight polyols present in the compositions may volatilize during the drying operation producing undesirable volatile organic compound (VOC) emissions. Some of these compositions are also in the form of emulsions, which can create processing and equipment difficulties during fiberglass manufacturing. Some of these formulations are also in the form of two part compositions requiring the user to mix the parts of the composition prior to use.